The invention relates to a method of continuously casting steel strands in continuous casting plants, wherein the steel is cast into the mould through one or more than one casting tubes reaching below the casting level in the mould and casting powder is continuously applied to the casting level in the mould.
Cracks in steel strands cause high losses of material and reduce the output advantage that the continuous casting process has relative to other casting processes. The cracks must be removed before the strand is processed, because otherwise the end product would have a surface that cannot be used.
There are various factors that cause cracks. They may form, e.g., because the strand guide does not correspond to the specified geometry. Then the strand is subjected to an increased deformation stress. Furthermore, tensions due to the water cooling of the strand increase the likelihood of the formation of cracks. Also the corrosion of the strand surface due to scales and casting slag contributes to the formation of cracks. Finally, the occurrence of cracks also essentially depends on the chemical composition of the material.
The above named influencing factors cannot be excluded, but they can be diminished to a certain extent, which requires a high degree of maintenance of the continuous casting plant and an exact observance of certain casting conditions. Despite such measures, however, there still remains the danger of the formation of cracks.